Method for realizing oil-based liquid super-lubricity in situ in super-lubricity system

Abstract

The invention discloses a method for realizing oil-based liquid super-lubricity in situ in a super-lubricity system. According to the super-lubricating system, any one of silicon nitride, silicon dioxide, zirconium oxide or tungsten steel and a carbon-based thin film serve as a friction pair, oil-based liquid serves as a lubricating agent, and pre-running-in lubricating liquid is dropwise added or coated on the surface of the friction pair in advance. The pre-running-in lubricating liquid is prepared from the following components in percentage by weight: 0.01%-15.0% of a friction modifier and the balance of polybasic fatty alcohol. The in-situ oil-based liquid super-lubricity realization method comprises the following steps: 1) dropwise adding a pre-running-in lubricating liquid to the surface of a friction pair and running in; and (2) after the surface of the friction pair is cleaned, oil-based liquid is dropwise added to the surface of the friction pair obtained in the step (1), and oil-based liquid super-lubricity can be achieved in situ. According to the method disclosed by the invention, robust super-lubricity of various oil-based liquids on the surface of the carbon-based thin film is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and in particular to a superlubricity system and a method for achieving in-situ superlubricity of oil-based liquids. Background Art

[0002] Carbon-based film is a new type of material that combines strength and lubrication. Carbon-based film materials can effectively reduce friction and wear of parts and components, and therefore have a wide range of applications in aerospace, aviation, and deep-sea shipbuilding. With the introduction of the concept of superlubricity, how to achieve robust superlubricity of carbon-based films has become a hot topic of research at home and abroad, especially the realization of oil-based liquid superlubricity on the surface of carbon-based films. Among them, the oil-based lubrication system is one of the most valuable superlubricity systems for engineering applications due to its high thermal stability, low volatility, and low susceptibility to environmental humidity; at the same time, the waste liquid of oil-based lubricants can be recycled, which is in line with my country's green and sustainable development concept.

[0003] However, the high chemical inertness of carbon-based films makes it difficult for them to undergo tribochemical reactions with oil-based liquids, making it impossible to achieve superlubricity. Summary of the invention

[0004] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] In response to the above-mentioned technical difficulties, the present application innovates a path to achieve super-lubricity, and provides a pre-running lubricant for carbon-based films that achieves super-lubricity of oil-based liquids, a preparation method thereof, a super-lubricity system, and a method for achieving super-lubricity of oil-based liquids in situ. The method described in the present application has achieved robust super-lubricity of a variety of oil-based liquids on the surface of carbon-based films.

[0006] The first aspect of the present application provides a pre-running-in lubricating fluid, which comprises the following components by weight percentage: a friction modifier: 0.01%-15.0%, and the balance polyhydric fatty alcohol.

[0007] In an exemplary embodiment, the pre-running lubricating fluid is composed of the following components by weight: friction modifier: 0.01%-15.0%, and the balance polyol.

[0008] In an exemplary embodiment, the friction modifier is C 1-10 Alkyl sulfate and C 1-10 One or two of alkyl sulfites; preferably C 1-8 Alkyl sulfate and C 1-8 One or two of alkyl sulfites, more preferably C 1-5 Alkyl sulfate and C 1-5 One or two of the alkyl sulfites.

[0009] In an exemplary embodiment, the structure of the alkyl sulfate is: R 1 O-SO2-OR 2 , where R 1 With R 2 Same or different C 1-5 alkyl.

[0010] In an exemplary embodiment, the structure of the alkyl sulfite is: R 3 OS(=O)-OR 4 , where R 3 With R 4 Same or different C 1-5 alkyl.

[0011] In an exemplary embodiment, the alkyl sulfate is selected from a mixture of one or more of diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and dipentyl sulfate in any proportion.

[0012] In an exemplary embodiment, the alkyl sulfite is selected from a mixture of one or more of diethyl sulfite, dipropyl sulfite, dibutyl sulfite, and diamyl sulfite in any proportion.

[0013] In an exemplary embodiment, the polyhydric fatty alcohol is a mixture of one or more fatty alcohols having 2 to 20 carbon atoms and not less than 2 hydroxyl groups in any proportion. The term "polyhydric fatty alcohol" used herein includes: chain hydrocarbon polyols and cyclic polyols, wherein the chain hydrocarbon polyols optionally include one or more ether groups, olefin groups or alkyne groups.

[0014] In an exemplary embodiment, the polyhydric fatty alcohol may be selected from one or more of triethylene glycol, ethylene glycol, propylene glycol (eg, 1,3-propylene glycol, 1,2-propylene glycol), and glycerol (eg, 1,3-propylene glycol, 1,2-propylene glycol).

[0015] In an exemplary embodiment, the friction modifier is selected from one or both of dipropyl sulfite and diethyl sulfate.

[0016] In an exemplary embodiment, the pre-running lubricating fluid is composed of the following components by weight percentage: 10% dipropyl sulfite and the balance triethylene glycol; or

[0017] The pre-running lubricant is composed of the following components by weight: 2% dipropyl sulfite, 3% diethyl sulfate and the balance ethylene glycol; or

[0018] The pre-running lubricant is composed of the following components by weight: 2% of dipropyl sulfite, 3% of diethyl sulfate, 5% of glycerol, 30% of ethylene glycol, 10% of propylene glycol, and 50% of triethylene glycol.

[0019] The second aspect of the present application provides a method for preparing the above-mentioned pre-running-in lubricating liquid, comprising: uniformly mixing a friction modifier and a polyol according to a ratio to obtain the pre-running-in lubricating liquid.

[0020] The third aspect of the present application provides a pre-running lubricating fluid prepared by the above method.

[0021] The fourth aspect of the present application provides an ultra-lubricating system, which uses any one of silicon nitride, silicon dioxide, zirconium oxide or tungsten steel and a carbon-based film as a friction pair, uses an oil-based liquid as a lubricant, and pre-drip or coats the pre-running lubricating liquid on the surface of the friction pair.

[0022] In an exemplary embodiment, the oil-based liquid is an unsaturated oil-based liquid;

[0023] Optionally, the oil-based liquid is selected from a mixture of one or more of oleic acid, castor oil, soybean oil, poly-alpha-olefin (PAO) and silicone oil in any proportion;

[0024] Optionally, the poly-alpha-olefin is selected from a mixture of one or more of PAO 2, PAO 4 and PAO 10 in any proportion;

[0025] Optionally, the silicone oil is selected from a mixture of one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, fluorinated silicone oil and amino silicone oil in any proportion.

[0026] In an exemplary embodiment, the super-lubricating system uses carbon-based film / silicon nitride ceramics as a friction pair.

[0027] In an exemplary embodiment, the carbon-based film is a hydrogen-free amorphous carbon-based film;

[0028] Optionally, the carbon-based film is selected from at least one of an amorphous carbon-based film (aC) and a tetrahedral amorphous carbon-based film (ta-C).

[0029] The fifth aspect of the present application provides a method for in-situ realization of oil-based liquid superlubricity in the above-mentioned superlubricity system, the method comprising:

[0030] 1) dripping or coating the pre-running lubricant onto the surface of the friction pair and running-in;

[0031] 2) After cleaning the surface of the friction pair, an oil-based liquid is added dropwise to the surface of the friction pair obtained in step 1), thereby achieving in-situ superlubricity of the oil-based liquid in the superlubricity system.

[0032] In an exemplary embodiment, step 1) includes: dripping or coating the pre-running lubricant onto the surface of the friction pair, and running for 0-120 minutes at a rotation speed of v1 and a Hertzian contact stress of P1, wherein the running time here does not include 0.

[0033] In an exemplary embodiment, step 2) includes: after cleaning the surface of the friction pair, dripping the oil-based liquid onto the surface of the friction pair obtained in step 1), and performing friction under the conditions of a rotation speed of v2 and a Hertzian contact stress of P2, so that the oil-based liquid superlubricity can be achieved in situ in the superlubricity system.

[0034] In an exemplary embodiment, the ranges of the rotation speeds v1 and v2 are:

[0035] 0mm / s≤v1≤300mm / s, 0mm / s≤v2≤1000mm / s, and v1≤v2.

[0036] In an exemplary embodiment, the ranges of the Hertzian contact stresses P1 and P2 are:

[0037] 0MPa<P1≤2000MPa, 0MPa<P2≤500MPa, and P1≥P2.

[0038] In an exemplary embodiment, the method comprises the following steps:

[0039] 1) dropping the pre-running lubricant onto or coating the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and running the pre-running lubricant for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 10% dipropyl sulfite and the balance triethylene glycol;

[0040] 2) After cleaning the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, methyl silicone oil is added to the surface of the carbon-based film / silicon nitride ceramic pair obtained in step 1), and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 89 MPa, so that oil-based liquid superlubricity can be achieved in situ in the superlubricity system.

[0041] In an exemplary embodiment, the method includes:

[0042] 1) dripping or coating a pre-running lubricant onto the surface of a tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, and running the pair for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 2% dipropyl sulfite, 3% diethyl sulfate, and the balance ethylene glycol;

[0043] 2) After cleaning the surface of the tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, PAO 4 is dropped onto the surface of the tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 90 MPa, so that oil-based liquid superlubricity can be achieved in situ in the superlubricity system.

[0044] In an exemplary embodiment, the method includes:

[0045] 1) dripping or coating a pre-running lubricant onto the surface of an amorphous carbon-based film aC / silicon nitride ceramic pair, and running the pair for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight: 2% dipropyl sulfite, 3% diethyl sulfate, 5% glycerol, 30% ethylene glycol, 10% propylene glycol, and 50% triethylene glycol;

[0046] 2) After cleaning the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, an oil-based liquid is dripped onto the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 87 MPa, so that the oil-based liquid superlubricity can be achieved in situ in the superlubricity system; wherein the oil-based liquid is composed of the following components by weight: 2% oleic acid, 20% methyl silicone oil, 50% PAO 2, and 28% PAO 4.

[0047] This application has the following technical effects:

[0048] 1. The present application provides a method for achieving in-situ superlubricity of oil-based liquids in a superlubricity system, which solves the technical problem that it is difficult to achieve superlubricity of oil-based liquids on the surface of carbon-based films, and has achieved robust superlubricity of a variety of oil-based liquids and their mixtures on the surface of carbon-based film / silicon nitride pairings.

[0049] 2. The superlubricious system and the method for achieving in-situ superlubricity of oil-based liquids of the present application have excellent adaptability to a variety of carbon-based films, are independent of the coating preparation method, have low sensitivity to parameters such as coating surface roughness and bonding strength, and have broad industrial application value.

[0050] 3. The oil-based liquid involved in the superlubricity system and the method for achieving in-situ superlubricity of oil-based liquid in the present application has high adaptability characteristics. Combined with the actual industrial lubrication environment, the friction coefficient can be controlled and adjusted through the reasonable design of components and content.

[0051] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0053] Figure 1 is the super-slip friction coefficient curve obtained in Example 1;

[0054] Figure 2 This is the super-slip friction coefficient curve obtained in Example 2;

[0055] Figure 3 This is the super-lubricating friction coefficient curve obtained in Example 3. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application will be described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0057] The present invention is further described in detail below in conjunction with specific examples, but the examples should not be construed as limiting the present invention. The raw materials of this application are all conventional products on the market.

[0058] Example 1

[0059] Pre-running-in lubricant: Mix 10% of dipropyl sulfite and the balance of triethylene glycol evenly according to weight percentage to obtain a pre-running-in lubricant.

[0060] Oil-based liquid: methyl silicone oil

[0061] Methods for achieving super-lubricity of oil-based liquids in situ:

[0062] 1) dropping the pre-running lubricant prepared above onto the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and running for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa;

[0063] 2) After cleaning the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, methyl silicone oil is added to the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 89 MPa, so that super-lubricity can be achieved in situ.

[0064] Example 2

[0065] Pre-running-in lubricant: 2% of dipropyl sulfite, 3% of diethyl sulfate and 95% of ethylene glycol are uniformly mixed according to weight percentage to obtain a pre-running-in lubricant.

[0066] Oil-based fluid: PAO 4

[0067] Methods for achieving super-lubricity of oil-based liquids in situ:

[0068] 1) dropping the pre-running lubricant prepared above onto the surface of the tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, and running for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa;

[0069] 2) After cleaning the surface of the tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, PAO 4 base oil is dropped onto the surface of the tetrahedral amorphous carbon-based film ta-C / silicon nitride ceramic pair, and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 90 MPa, thereby achieving super-lubricity in situ.

[0070] Example 3

[0071] Pre-running-in lubricant: Evenly mix 2% of dipropyl sulfite, 3% of diethyl sulfate, 5% of glycerol, 30% of ethylene glycol, 10% of propylene glycol, and 50% of triethylene glycol by weight to obtain a pre-running-in lubricant.

[0072] Oil-based liquid: 2% of oleic acid, 20% of methyl silicone oil, 50% of PAO 2 base oil, and 28% of PAO 4 base oil are uniformly mixed according to weight percentage to obtain an oil-based liquid.

[0073] Methods for achieving super-lubricity of oil-based liquids in situ:

[0074] 1) dropping the pre-running lubricant prepared above onto the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and running for 10 minutes at a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa;

[0075] 2) After cleaning the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, the above-mentioned oil-based liquid is dropped onto the surface of the amorphous carbon-based film aC / silicon nitride ceramic pair, and friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 87 MPa, so that super-lubricity can be achieved in situ.

[0076] Figures 1 to 3 The following results are shown for Examples 1-3:

[0077] Figures 1 to 3 It includes two steps, namely step 1 and step 2, and step 1 and step 2 are disconnected at 600s-800s in the horizontal axis of the figure; wherein: step 1 is a graph showing the change of COF (coefficient of friction) over time in the process of using the pre-running lubricating fluid of an embodiment of the present invention to treat the surface of the friction pair composed of a carbon-based film and a silicon nitride ceramic; step 2 is a graph showing the change of COF (coefficient of friction) over time in the process of using the pre-running lubricating fluid of an embodiment of the present invention to treat the surface of the friction pair composed of a carbon-based film and a silicon nitride ceramic; and step 2 is a graph showing the change of COF (coefficient of friction) over time after cleaning the surface of the friction pair and dripping an oil-based liquid after step 1, and the average COF of the surface of the friction pair is about 0.01, realizing the super-lubricity of the oil-based liquid.

[0078] The above embodiments are all preferred embodiments of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for realizing oil-based liquid superlubricity in situ in a superlubricity system, characterized in that: The super-lubricating system uses any one of silicon nitride, silicon dioxide, zirconium oxide or tungsten steel and a carbon-based film as a friction pair, uses an oil-based liquid as a lubricant, and pre-drips or coats a pre-running lubricant on the surface of the friction pair; the method comprises: 1) dripping or coating the pre-running lubricant onto the surface of the friction pair and running-in; 2) After cleaning the surface of the friction pair, the oil-based liquid is dripped onto the surface of the friction pair obtained in step 1), so that the oil-based liquid superlubricity can be achieved in situ in the superlubricity system.

2. The method according to claim 1, characterized in that The pre-running lubricant is composed of the following components by weight: friction modifier: 0.01%-15.0%, and the balance polyhydric fatty alcohol; and / or The oil-based liquid is an unsaturated oil-based liquid.

3. The method according to claim 1 or 2, characterized in that: The friction modifier is C 1-10 Alkyl sulfate and C 1-10 One or two of alkyl sulfites; and / or The polyhydric fatty alcohol is a mixture of one or more fatty alcohols having 2 to 20 carbon atoms and not less than 2 hydroxyl groups in any proportion.

4. The method according to claim 3, characterized in that The structure of the alkyl sulfate is: 1 O-SO2-OR 2 , where R 1 With R 2 Same or different C 1-5 Alkyl; and / or The structure of the alkyl sulfite is: 3 OS(=O)-OR 4 , where R 3 With R 4 Same or different C 1-5 alkyl.

5. The method according to claim 4, characterized in that The alkyl sulfite is selected from a mixture of one or more of diethyl sulfite, dipropyl sulfite, dibutyl sulfite and diamyl sulfite in any proportion; and / or The alkyl sulfate is selected from a mixture of one or more of diethyl sulfate, dipropyl sulfate, dibutyl sulfate and dipentyl sulfate in any proportion.

6. The method according to claim 1 or 2, characterized in that: The polyhydric fatty alcohol is selected from one or more of triethylene glycol, ethylene glycol, propylene glycol and glycerol; and / or The friction modifier is selected from one or both of dipropyl sulfite and diethyl sulfate.

7. The method according to claim 1 or 2, characterized in that: The oil-based liquid is selected from a mixture of one or more of oleic acid, castor oil, soybean oil, poly-α-olefin and silicone oil in any proportion; Optionally, the poly-alpha-olefin is selected from a mixture of one or more of PAO 2, PAO 4 and PAO 10 in any proportion; Optionally, the silicone oil is selected from a mixture of one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, fluorinated silicone oil and amino silicone oil in any proportion.

8. The method according to claim 1 or 2, characterized in that: The friction pair uses carbon-based film / silicon nitride ceramic as the friction pair; Optionally, the carbon-based film is a hydrogen-free amorphous carbon-based film; Optionally, the carbon-based film is selected from at least one of an amorphous carbon-based film and a tetrahedral amorphous carbon-based film.

9. The method according to claim 1 or 2, characterized in that: Step 1) comprises: dripping or coating the pre-running lubricant onto the surface of the friction pair, and running for 0-120 minutes at a rotation speed of v1 and a Hertzian contact stress of P1, wherein the running time here does not include 0; Step 2) comprises: after cleaning the surface of the friction pair, dripping the oil-based liquid onto the surface of the friction pair obtained in step 1), and performing friction under the conditions of a rotation speed of v2 and a Hertzian contact stress of P2, so that the oil-based liquid superlubricity can be achieved in situ in the superlubricity system.

10. The method according to claim 9, characterized in that The range of the rotation speeds v1 and v2 is: 0mm / s≤v1≤300mm / s, 0mm / s≤v2≤1000mm / s, and v1≤v2; Optionally, the range of the Hertzian contact stresses P1 and P2 is: 0MPa<P1≤2000MPa, 0MPa<P2≤500MPa, and P1≥P2.

Images